Question

Why might it make more sense to think of photoreceptors as darkness sensors rather than as light sensors

Answer 1

The photoreceptors could be called darkness sensors rather than as light sensors because of the no. of rods cells. The photoreceptors are made up of two types of cells namely rods and cones. The roda are the cells that can detect very low light and are 120 million in number. whereas, the cones are only 6 million in number and are sensitive in light. The rod cells can work in dark as they require very low light but cannot provide colorful vision which is the feature of cones cells and since rods cells clearly outnumber cones we could say photoreceptors as darkness sensors rather than light sensors.